Due to the increasing density of integrated circuits and the increasing number of functions that are integrated into the integrated circuit, each pin associated with a packaged device is utilized to serve multiple functions. For example, some integrated circuits are operated in a test mode or in an operating mode. In the test mode, the operating mode is disabled and signals input thereto are then recognized as being test signals. Typically, one pin is dedicated to selecting the test mode or the operating mode. Thereafter, input pins can typically serve two different input functions. When the pins are used in programming applications with three-state inputs, typically small impedances are utilized. For example, the pin is allowed to float or be connected directly to the positive or negative rail.
Although output driver pins have been utilized for input/output functions, these functions are typically separate operations, i.e., the output device is driven by the pin, and an output function is typically not present when an input signal is applied thereto. This is due to the fact that the impedance presented to the pin by the output device interferes with the input function. Further, the input function typically also requires a low impedance. For example, if an input required a low logic state signal to be applied thereto, the signal could not be applied thereto while the active device was attached, as this may cause excessive current to flow through the active device and may, in fact, turn the active device on if it were some device such as a display element.